Ellington, Justice. This case arose from a taxpayer grievance concerning whether the Fulton County Board of Tax Assessors (the “Board”) had been diligent in determining that the Atlanta Falcons Stadium Company LLC (“StadCo”) had a usufruct interest in the Mercedez-Benz Stadium that was not subject to ad valorem taxation. In 2017, Albert E. Love and other Fulton County taxpayers (“the appellants”) sued the Board, the individual members of the Board, and the Board’s Chief Appraiser, seeking mandamus and other relief.[1] Since then, the suit has been dismissed, appealed to the Court of Appeals, see Love v. Fulton County Board of Tax Assessors, 348 Ga. App. 309 (821 SE2d 575) (2018), remanded, amended to add claims and intervenors, and then dismissed again. At issue in this appeal is whether the trial court properly dismissed the appellants’ fourth amended petition, which asserted claims for mandamus, declaratory and injunctive relief, and a refund of taxes paid. In support of its claims, the appellants asserted that the Board and its members had committed a gross abuse of discretion by failing to find that StadCo had a leasehold interest in the stadium that is subject to ad valorem taxation. The appellants also asserted that the Board’s decision was based on an “unconstitutionally adopted” exemption codified in OCGA § 10-9-10. The appellees and intervenors StadCo and the Georgia World Congress Center (“GWCCA”) answered and filed motions arguing, among other things, that the Board had properly determined that StadCo’s interest was a non-taxable usufruct after conducting an investigation and holding a hearing at which they considered evidence concerning the nature of StadCo’s interest. They also argued that the Board’s decision was not based on OCGA § 10-9-10 but on an evaluation of agreements entered into between the intervenors prior to the construction of the stadium. In its order dismissing the case, the trial court addressed each of the appellants’ claims and found that the petition lacked any legal basis for recovery. On appeal, the appellants contend that the trial court erred in dismissing the petition, allegedly sua sponte, arguing primarily that the trial court had applied an incorrect standard of review. They also contend that the trial court erred in declining to find OCGA § 10-9-10 unconstitutional. For the following reasons, we see no error and affirm the judgment. A motion to dismiss for failure to state a claim upon which relief may be granted should not be sustained unless (1) the allegations of the complaint disclose with certainty that the claimant would not be entitled to relief under any state of provable facts asserted in support thereof; and (2) the movant establishes that the claimant could not possibly introduce evidence within the framework of the complaint sufficient to warrant a grant of the relief sought. (Footnotes omitted.) Anderson v. Flake, 267 Ga. 498, 501 (2) (480 SE2d 10) (1997). See also OCGA § 9-11-12 (b) (6). In assessing whether a claim should be dismissed, a court may consider exhibits attached to and incorporated into the complaint and answer. See OCGA § 9-11-10 (c) (“A copy of any written instrument which is an exhibit to a pleading is a part thereof for all purposes”); Minnifield v. Wells Fargo Bank, N. A., 331 Ga. App. 512, 514-515 (2) (771 SE2d 188) (2015) (“When considering a motion to dismiss for failure to state a claim, a trial court may consider exhibits attached to and incorporated into the complaint and answer.” (citation omitted)). To the extent there are inconsistences between the allegations in the complaint and exhibits attached to the complaint, the exhibits control. See Lord v. Lowe, 318 Ga. App. 222, 223-224 (741 SE2d 155) (2012). The appellate court “review[s] de novo the trial court’s ruling on the [defendants'] motion to dismiss, accepting as true all well- pled material allegations in the complaint and resolving any doubts in favor of [the plaintiff].” Greene County School Dist. v. Circle Y Constr., 291 Ga. 111, 112 (728 SE2d 184) (2012). 1. According to the fourth amended petition and its exhibits, before the new stadium was built, the GWCCA owned and operated the Georgia Dome, which was the home venue for the Atlanta Falcons professional football team. Prior to investing $1.5 billion to construct the new stadium, the parties involved in the project entered into a number of agreements concerning the tax ramifications of their interests in the stadium. On April 5, 2013, GWCCA, StadCo, and Atlanta Falcons Football Club, LLC (the “Club”) entered into a “Memorandum of Understanding for a Successor Facility to the Georgia Dome” (the “MOU”). That same day, GWCCA, the Atlanta Development Authority d/b/a Invest Atlanta (“Invest Atlanta”), and StadCo entered into a “Tri-Party Memorandum of Understanding for a Successor Facility to the Georgia Dome” (the “Tri-Party MOU”). With respect to taxation, the MOU states that “[n]either [StadCo] nor the GWCCA expect any ad valorem taxes to be payable with respect to their respective interests in such real property and improvements for the [stadium project], and neither Party will in any event assume or undertake any ad valorem tax responsibilities or liabilities of the other.” The MOU further provided that “StadCo shall have received confirmation from the [Board] or other appropriate governmental authority in form reasonably satisfactory to StadCo that StadCo’s and [the Club's] rights with respect to the [stadium] under the License Agreement and related agreements will constitute a usufruct.”[2] On August 6, 2013, StadCo’s counsel provided the Board and the Board’s chief appraiser with a lengthy legal memorandum analyzing the terms of the MOU and Tri-Party MOU, which asserted that, “based on the significant amount of control over the [stadium] that is retained by the GWCCA, StadCo’s License with respect to the [stadium] creates a usufruct and not an estate for years.” On August 22, 2013, at a regularly scheduled meeting of the Board, a motion was introduced to consider whether StadCo’s interest would be exempt from ad valorem taxes. After discussing the motion, the Board unanimously voted that StadCo’s interest in the stadium was not subject to ad valorem taxes. That same day, the Board issued a “Statement of Intent to Exempt Real and Personal Property” (the “Exemption Decision”), which expressly provides that StadCo’s interest in the stadium would not be subject to ad valorem taxation. The Board’s Exemption Decision states that it was based on its evaluation of the MOU and Tri-Party MOU. The MOU is an 86-page document that outlines in detail the expectations and understanding of GWCCA, StadCo, and the Club with respect to the financing, construction, development, and operation of the stadium, including the terms of proposed lease or license agreements. The Tri- Party MOU is a 99-page document that similarly outlines the expectations and understanding between the parties with respect to additional rights and obligations concerning the use of the stadium. The Board’s Exemption Decision provides, in relevant part: Based on the [MOU, the Tri-Party MOU], and pursuant to OCGA § 10-9-10[[3]], it is the intent of the Fulton County Board of Assessors to recognize the exempt status to the real and business personal property included in the [MOUs] and the lease/license of the stadium property including all buildings, parking areas and other real and personal property to be constructed and utilized under the terms of the lease/license. This exemption will take effect upon commencement of construction of the stadium and remain in effect throughout the term of the lease/license agreement provided that the terms of the [MOUs] are not altered and the lease/license does not substantially change the terms and conditions of the [MOUs]. Any changes or alterations of such [MOUs] or lease/license agreements will be subject to review by the Fulton County Board of Assessors to ensure that such changes do not alter the relationship of the parties substantially that would create a change that would render the property taxable under Georgia Law. Based on the Exemption Decision, StadCo was not required to nor has it paid ad valorem taxes on its right to use the stadium. On May 18, 2015, StadCo, consistent with the MOU and Tri-Party MOU, entered into a Stadium License and Management Agreement (“the SLM Agreement”) with GWCCA. In the SLM Agreement, the GWCCA formally granted StadCo a usufruct in the stadium improvements and set forth the terms and conditions for the development, construction, and operation of the stadium between the GWCCA, as licensor, and StadCo, as licensee. The SLM Agreement provided that the GWCCA did not transfer an estate for years, a tenancy, a leasehold interest, or other real property interest. The term of the SLM Agreement runs through February 28, 2047, and is subject to extension or renewal by the parties. Because the Board’s Exemption Decision provided that the tax exemption remains in effect throughout the term of the lease/license agreement described in the MOUs (provided that any subsequent agreement does not substantially change the terms and conditions of the MOUs), the exemption remains in effect until February 28, 2047, when the SLM Agreement is set to expire. The appellants filed suit on October 17, 2017. The petition included two counts for a writ of mandamus seeking to have the Board and its members reevaluate the taxability of StadCo’s interest in the stadium. It also included a count for a declaratory judgment, asserting that StadCo’s interest in the stadium was not a usufruct but, rather, a taxable leasehold interest. The appellants subsequently amended the petition to add a fourth count seeking to enjoin the Board and its members from treating StadCo’s leasehold interest in the stadium as tax exempt, and a fifth count seeking a declaration that OCGA § 10-9-10, as it was amended in 1989, was unconstitutional. Thereafter, the Board filed a motion to dismiss the amended petition for failure to state a claim upon which relief may be granted. On March 13, 2018, the trial court granted the Board’s motion to dismiss. The trial court found that the Board “exercised its discretion in determining that StadCo’s contractual rights in the [stadium] were not subject to ad valorem taxes.” It further found that “[the Board] and its members reviewed the MOU and the Tri- Party MOU, evaluated StadCo’s contractual rights in the [stadium], determined that the contractual rights constituted a non-taxable usufruct, and prepared the [Exemption Decision], which was voted on and unanimously approved.” The trial court further found: “Indeed, it is clear based upon the pleadings alone that the [Board] considered this issue and made a decision based upon all of the information before it[.]” The trial court noted that “ Petitioners may have preferred a different result, but that does not entitle them to mandamus relief against the [Board] and its members.” Finally, the court found that “[t]he terms of the SLM Agreement are consistent with the terms contemplated by the MOU and the Tri-Party MOU,” and that “Petitioners failed to rebut (or even address) Respondents['] assertion that the SLM Agreement is consistent with the MOU and the Tri-Party MOU, which assertion is supported by the Exhibits attached to the Amended Petition and Second Amended Petition and adopted by the Court as a finding of fact.” The appellants appealed this first dismissal order to the Court of Appeals. The court held that the trial court properly considered the exhibits to the petitions in dismissing the amended petition, and that any findings based on the trial court’s review of those exhibits did not convert the motion to dismiss into a motion for summary judgment. See Love, 348 Ga. App. at 315-316 (1). The appellants urged the Court of Appeals to hold that the Board and its members had a nondiscretionary duty to investigate and determine whether property in the county was subject to ad valorem taxation. They argued that the amended petition and exhibits showed that the Board failed to exercise this duty because the Board did not review the SLM Agreement to determine whether StadCo’s interest in the stadium was taxable. Thus, the appellants contended, if their amended complaint were accepted as true, they were entitled to a writ of mandamus compelling the Board to investigate and determine whether StadCo’s interest was subject to ad valorem taxation based on the SLM Agreement. The Court of Appeals held, however, that the appellants had failed to state a mandamus claim under OCGA § 48-5-299, which pertains to the duties of a county board of tax assessors.[4] The court held that OCGA § 48-5-299 “affords the [Board] discretion in the process it follows to investigate and inquire into whether property is subject to ad valorem property taxation.” Love, 348 Ga. App. at 318 (2). It also stated that it is within the Board’s discretion to determine the manner in which to conduct its investigation, what evidence should be reviewed, and how it reaches decisions. Id. The court went on to explain that: Given that the [Board] is afforded discretion in how to conduct an investigation, mandamus relief would be appropriate only if the Board failed entirely to conduct an investigation and reach a decision regarding the tax status of [StadCo's] interest in the New Stadium. However, the plaintiffs’ amended petition and attached exhibits disclose with certainty that the [Board] investigated the taxability of [StadCo's] interest and reached a decision on that question. In this regard, the [Exemption Decision] and the minutes from the August 22, 2013 [Board] meeting attached to the plaintiffs’ amended petition reflect that the Board reviewed the MOU and the Tri-Party MOU, determined that the interest of [StadCo] was not subject to ad valorem taxation, and specified that the Board’s decision would “take effect upon commencement of construction of the [New Stadium]” and remain in effect throughout the term of the parties’ agreement, with the caveat that any substantial changes in the final agreement reached by the parties could lead the Board to reconsider its decision. Accordingly, as reflected by the amended petition and attached exhibits, there was not a total failure by the [Board] to investigate and reach a decision, and mandamus relief would not be an appropriate mechanism to compel the Board to conduct its investigation in a particular manner under OCGA § 48-5-299 (a). (Citations omitted; emphasis supplied.) Love, 348 Ga. App. at 318-319 (2). The Court of Appeals concluded that the mandamus claims brought in the amended petition against the Board members failed as a matter of law. See id. at 319 (3). The court noted, however, that mandamus relief may be appropriate where an official, acting in an official capacity, performs a discretionary duty in a manner so unreasonable, arbitrary, and capricious that it amounts to a gross abuse of discretion. See id. at 319 n.8. The court did not address that circumstance because the appellants had not framed their mandamus claim to allege a gross abuse of discretion. The Court of Appeals also affirmed the dismissal of appellants’ claims for declaratory and injunctive relief against the Board as well as against the individual defendants in their official capacities on sovereign immunity grounds. See id. at 320 (4) n.9. However, the court reversed the trial court’s order dismissing the counts as asserted against the individual defendants, in their individual capacities only, for a declaratory judgment as to whether the SLM Agreement transferred to StadCo a taxable leasehold interest in the stadium, and for an injunction to prevent the Board members from implementing the Exemption Decision. And, finally, the court reversed the trial court’s dismissal of the appellants’ challenge to the constitutionality of OCGA § 10-9-10 on mootness grounds. See Love, 348 Ga. App. at 320-321 (4), (5). The Court of Appeals remanded the case for the resolution of these matters. After the case was remanded to the trial court, the appellants amended their petition a third time and the trial court permitted GWCCA and StadCo to intervene. Thereafter, GWCCA filed a motion to dismiss, and StadCo filed a motion for summary judgment. Then, on October 22, 2019, the appellants filed their fourth amended petition. The fourth amended petition restates most of the appellants’ earlier claims, including counts for: (a) a writ of mandamus based on the Board members’ “gross abuse of discretion” in issuing and in failing to review the Exemption Decision; (b) injunctive relief to enjoin and restrain the Board members in their individual capacities from implementing the Exemption Decision; (c) a judgment against the Board members in their individual capacities declaring that the SLM Agreement granted StadCo a taxable leasehold interest; (d) a judgment against the Board, as well as against the Board members and the Chief Appraiser in their official and individual capacities, declaring that OCGA § 10-9-10, as amended in 1989, is unconstitutional. The fourth amended petition also added a new claim seeking an order directing Fulton County and the Fulton County Tax Commissioner to issue a refund under OCGA § 48-5-380 to every county resident who was allegedly overcharged for property taxes in 2018 and 2019 based on the Board’s alleged failure to assess taxes against StadCo in connection with its interest in the stadium (Count V).[5] On April 22, 2020, the trial court entered an order dismissing the fourth amended petition in its entirety for failing to state a claim upon which relief may be granted. This appeal followed. 2. The appellants contend that the trial court erred in allegedly dismissing their fourth amended petition sua sponte. They also argue at length that the trial court erred by evaluating their claims under the “any evidence” standard applicable to appellate review of administrative decisions instead of the legal standard a trial court must apply when considering whether to grant a motion to dismiss. Our review of the trial court’s dismissal order is de novo. See Greene County School District, 291 Ga. at 112. First, pretermitting whether the trial court dismissed the petition on its own, it had the authority to do so. See Roberts v. DuPont Pine Prods., 352 Ga. App. 659, 661 (2) (835 SE2d 661) (2019) (“A trial court has the authority to dismiss claims sua sponte if it can determine from the pleadings that the claims cannot succeed as a matter of law.” (citation omitted)).[6] Second, the trial court evaluated the petition under the legal standard applicable to motions to dismiss, expressly stating that dismissal for failure to state a claim was appropriate “where a complaint lacks any legal basis for recovery.” The trial court referenced several cases that correctly explain or elaborate on this legal standard, including the trial court’s authority to consider exhibits attached to and incorporated into a petition.[7] Contrary to the appellants’ contentions, the trial court did not apply an “any evidence” standard of review. Rather, in discussing how the Board had evaluated StadCo’s interest in the stadium and reached its exemption decision, the trial court explained that “it is helpful to put this case in its proper context,” stating that the appellants were collaterally attacking an agency decision, one that, if appealed to a superior court, would be entitled to great deference under the “any evidence” standard.[8] Having concluded that the trial court applied the correct legal standard in dismissing the appellants’ fourth amended petition, and considered only the appellants’ “pleadings and their attachments” in concluding that each claim contained in the petition failed as a matter of law,[9] we now evaluate whether the trial court properly dismissed those claims. 3. (a) The appellants sought a writ of mandamus based upon the Chief Appraiser’s and the Board members’ (collectively “Board members”) alleged “gross abuse of discretion” in the issuance of the Exemption Decision as well as in the alleged failure to reconsider the Exemption Decision in light of the SLM Agreement.[10]Specifically, the appellants contended that none of the agreements that StadCo had entered into, including the SLM Agreement, “were ever investigated, evaluated, analyzed, or reviewed as to whether they altered or changed the ad valorem tax status or exempt status of StadCo’s real property interest” in the stadium. The appellants also asserted that the Board members had “failed and refused to perform a diligent investigation” into whether “the SLM Agreement has materially altered the relationship between the GWCCA and StadCo, from an ad valorem property tax standpoint.” OCGA § 9-6-20 provides, in relevant part: All official duties should be faithfully performed, and whenever, from any cause, a defect of legal justice would ensue from a failure to perform or from improper performance, the writ of mandamus may issue to compel a due performance if there is no other specific legal remedy for the legal rights [.] Mandamus is “an extraordinary remedy to compel a public officer to perform a required duty when there is no other adequate legal remedy.” (Citation and punctuation omitted.) R. A. F. v. Robinson, 286 Ga. 644, 646 (1) (690 SE2d 372) (2010). “The writ of mandamus is properly issued only if (1) no other adequate legal remedy is available to effectuate the relief sought; and (2) the applicant has a clear legal right to such relief.” (Citation and punctuation omitted.) Ga. Assn. of Professional Process Servers v. Jackson, 302 Ga. 309, 312 (2) (806 SE2d 550) (2017). Further, [f]or mandamus to issue, the law must not only authorize the act to be done, but must require its performance. Where performance is required by law, a clear legal right to relief will exist either where the official or agency fails entirely to act or where, in taking such required action, the official or agency commits a gross abuse of discretion. (Citation and punctuation omitted.) Id. at 312-313 (2). See also OCGA § 9-6-21 (a) (“Mandamus shall not lie as . . . to a public officer who has an absolute discretion to act or not to act unless there is a gross abuse of such discretion. However, mandamus shall not be confined to the enforcement of mere ministerial duties.”). A gross abuse of discretion occurs where an official performs a discretionary duty in a manner that is arbitrary, capricious, and unreasonable. See Massey v. Georgia Board of Pardons & Paroles, 275 Ga. 127, 128 (2) (562 SE2d 172) (2002). The trial court determined that the appellants’ mandamus claim had, in part, been resolved in the appellees’ favor when the Court of Appeals affirmed the previous order dismissing the appellants’ original mandamus claim. The Court of Appeals held that the trial court did not err in dismissing the mandamus claim as it had been framed in the previous petition because, although the Board members had a clear legal duty under OCGA § 48-5-299 (a) to investigate diligently and to inquire into the taxability of StadCo’s interest, “there was not a total failure by the [Board members] to investigate and reach a decision, and mandamus relief would not be an appropriate mechanism to compel the [Board members] to conduct its investigation in a particular manner under OCGA § 485-299 (a).” Love, 348 Ga. App. at 319 (2). Thus, that the Board members had exercised their discretion in investigating and deciding whether StadCo’s interest was tax exempt became the law of the case.[11] What remained of the mandamus claim for the trial court to resolve was whether the Board members had exercised that discretion in a manner that was unreasonable, arbitrary, and capricious. The trial court concluded that the facts asserted in the pleadings and exhibits to the fourth amended petition showed that the Board members performed their duty to investigate diligently and to inquire into whether StadCo’s interest was subject to ad valorem taxation. They considered arguments and documentary evidence presented during the Board’s August 22, 2013 hearing, including the MOUs. The Exemption Decision was expressly based on evidence presented to the Board at the hearing. And although the evidence before the Board “may not have been overwhelming,” as the trial court observed, the evidentiary concerns expressed by the appellants were “neither remarkable nor a sufficient basis to find that the [Board members had] acted arbitrarily or capriciously in determining that StadCo enjoyed a non-taxable usufruct interest.”[12] Further, when the Board members made the Exemption Decision, they did so “with the caveat that any substantial changes in the final agreement reached by the parties could lead the Board to reconsider its decision.” The trial court then considered the SLM Agreement, as it was authorized to do, and determined that the agreement “did not expand or extend, either temporally or in any other materially relevant manner, StadCo’s interest in GWCCA’s property.”[13] Thus, there was nothing in the SLM Agreement that would have triggered the Board members’ duty to reevaluate the tax exempt status of StadCo’s interest in the stadium. The trial court concluded: Thus a writ directing [the Board] to review subsequent agreements that merely fleshed out operational details (and did not materially change essential terms) of the [... MOU and Tri-Party MOU that the Board] originally assessed to transfer only a usufruct interest would be pointless. Moreover, it would be prescribing the method [the Board] is to use in conducting (and extending) its investigations, which, as previously stated, [this court] is not free to do. Thus, the allegations of the fourth amended petition disclosed with certainty that the appellants would not be entitled to relief under any state of provable facts asserted in support of their mandamus claim. Nor could they introduce evidence within the framework of the complaint sufficient to warrant a writ of mandamus. Consequently, the trial court did not err in dismissing the appellants’ mandamus claim. See R. A. F., 286 Ga. at 646 (1) (The trial court correctly found that the petition for mandamus is subject to dismissal because appellants failed to state a claim for mandamus relief.). (b) The appellants sought to enjoin the Board members in their individual capacities from continuing to implement the Exemption Decision. The trial court correctly concluded that the appellants’ claim for injunctive relief failed because, as explained in Division 3 (a), supra, the fourth amended petition and exhibits showed that the Board members’ Exemption Decision was founded on evidence that StadCo’s interest constituted a usufruct; they did not exercise their discretion in an unreasonable, arbitrary, or capricious manner that would constitute a gross abuse of duty; and the SLM agreement did not materially change the nature of StadCo’s interest in the stadium. Consequently, the appellants failed to show any legal basis for injunctive relief. See Ianicelli v. McNeely, 272 Ga. 234, 236 (2) (527 SE2d 189) (2000) (The trial court properly dismissed appellant’s claim for injunctive relief because the acts he sought to enjoin did not establish a violation of public duty as a matter of law.).[14] (c) The appellants brought a claim against the Board members in their individual capacities for a judgment declaring that the SLM Agreement conveyed a taxable estate for years as opposed to a nontaxable usufruct. The trial court explained that the appellants’ claim for a declaratory judgment was subject to dismissal because, even if the Board members’ Exemption Decision (or failure to reconsider that decision) was arbitrary, capricious, or simply wrong in light of the SLM Agreement, the appellants did not face any uncertainty because of the Exemption Decision or the SLM Agreement. This ruling was correct.[15] The Declaratory Judgment Act is designed to settle and afford relief from uncertainty and insecurity with respect to rights, status, and other legal relations, see OCGA § 94-1, and the object of the declaratory judgment is to permit determination of a controversy before obligations are repudiated or rights are violated. The proper scope of declaratory judgment is to adjudge those rights among parties upon which their future conduct depends. Such relief is authorized when there are circumstances showing a necessity for a determination of the dispute to guide and protect the plaintiff from uncertainty and insecurity with regard to the propriety of some future act or conduct, which is properly incident to his alleged rights and which if taken without direction might reasonably jeopardize his interest. (Citations and punctuation omitted.) Walker v. Owens, 298 Ga. 516, 518-519 (783 SE2d 114) (2016). Because the appellants did not show they were in a position of uncertainty as to an alleged right, the trial court properly dismissed their claim for a declaratory judgment. See Baker v. City of Marietta, 271 Ga. 210, 214 (1) (518 SE2d 879) (1999) (“Where the party seeking declaratory judgment does not show it is in a position of uncertainty as to an alleged right, dismissal of the declaratory judgment action is proper; otherwise, the trial court will be issuing an advisory opinion, and the Declaratory Judgment Act makes no provision for a judgment that would be advisory.” (citations and punctuation omitted)). (d) The appellants also sought a judgment declaring that OCGA § 10-9-10, as amended, was unconstitutional. The appellants argued that, prior to its amendment in 1989, OCGA § 10-9-10 contained a clause that prohibited the GWCCA from extending its tax exempt status “to any lessee or other private person or entity.” See 1989 Ga. L. p. 1198. The appellants argue that “the removal of this clause expanded the class of property holders entitled to the GWCCA tax exemption,” and, because the amendment took effect without a statewide referendum, it was unconstitutional. The appellants fail to acknowledge, however, that the trial court dismissed this count of the petition on an alternate ground. The trial court held as follows: The most basic reason why [the Petitioners'] challenge fails is that that [OCGA § 10-9-10's] constitutionality has no bearing on the Exemption Decision. If [that Code section], as amended in 1989, created (illegally) the exemption Petitioners argue it did, i.e., an automatic exemption for private leaseholders of GWCCA’s property, then that exemption would not be dependent on the terms of the MOUs entered into between StadCo and GWCCA. (Nor would the content and effect of the SLM Agreement matter.) Rather, all that [the Board] would have needed to determine was that GWCCA was leasing its property to StadCo . . . [and] GWCCA’s statutory exemption would automatically transfer to the lessee. Here, however, the [Board] considered the details of the MOUs, repeatedly referenced the MOUs in its Exemption Decision, and even noted that its decision was dependent not on [OCGA § 109-10] but on the terms of the MOUs, such that, if those terms were materially changed, [the Board's] exemption ruling might also change. Thus, while [the Board] could have been a tad clearer in its Exemption Decision by stating directly (instead of obliquely) that it found that GWCCA was transferring to StadCo a usufruct interest in its property, the terms of the Exemption Decision imply that conclusion and make sense only under that conclusion. In other words, [the Board] unanimously found that the interest GWCCA conveyed to StadCo constituted a usufruct, something that is exempt from taxation not because of OCGA § 10-9-10 . . . but because a usufruct interest is not an estate and so is not taxable. …This simple fact makes the constitutionality of [OCGA § 10-9-10] irrelevant and is reason enough to find, as a matter of law, that Count III should be dismissed. We agree with this reasoning. In light of the trial court’s correct conclusion that the Board did not rely on an exemption allegedly expressed in OCGA § 10-9-10, but rather determined that StadCo’s interest was a nontaxable usufruct,[16] we need not reach the trial court’s alternative ruling on the merits of the appellants’ challenge to the constitutionality of the statute. (e) Finally, the appellants contend that the trial court erred in dismissing their claim for a tax refund on the ground that the claim was moot. In the fourth amended petition, the appellants asserted a new claim against Fulton County and the Fulton County Tax Commissioner, pursuant to OCGA § 48-5-380, seeking a refund of taxes that Fulton County taxpayers had allegedly illegally paid to the county. The trial court, however, did not allow the appellants to amend the petition to add Fulton County or the Fulton County Tax Commissioner as parties. In a footnote to the portion of its order denying the appellants’ motion to add parties, the trial court stated: “This ruling arguably has the effect of dismissing Count V, which seeks a refund for the class from the County and the Tax Commissioner. Without those party Respondents, there is no Count V.” The appellants have not challenged this ruling. Consequently, we need not address the trial court’s alternative “mootness” rationale for dismissing the appellants’ claim for a refund. Judgment affirmed. All the Justices concur, except Peterson and Bethel, JJ., not participating, and McMillian, J., disqualified.
